In motocaching there are many riders who want to "find as many as possible" and therefore they actually want to ride your route. It's good to make it relatively easy by making a short route (e.g. 10 to 40 miles).
If you make a short route (for example instead of including several roads for a day trip): - Riders that come a long way to your cache have a chance to log a find. - It's easier to "find" your cache on the way to some other place (for example if riding from A to B there may not be enough time to ride a loop that is located between A and B. If a cache includes just one quarter or half of the loop it's much easier). - If you don't want to do multiple caches, then someone else will add the other great roads that are not included in your route. - When someone is planning to visit several caches it's much easier to fit a short route into the plan. - Even if the map seems "empty" when you are making your cache, there will most probably be other caches nearby that people want to visit too. Again, short routes makes it easier to plan a trip.